The present invention relates to a method of containing compressed gas and to systems for carrying out such containment; and, particularly to such method and systems for storing hydrogen and other potentially explosive gases in a safe environment.
The problem of creating safe, capacious and convenient storage for compressed gas (predominantly hydrogen), is one of the most important aspects of hydrogen energy development [1-3]. Some hydrogen storage methods currently available are [4-8]:
Compressed gaseous hydrogen in gas-cylinders;
Liquid hydrogen at low temperatures in Dewar flasks;
Chemically combined hydrogen in hydride powder canisters;
Physical-chemical absorbed hydrogen in carbon nanotubes.
Each of these methods has merits and demerits. Hydride storage material is capable of spontaneous ignition in air. They show complexities associated with the accumulation and extraction of hydrogen. Finally, they are so very expensive that they can not be considered for large-scale use as a hydrogen storage medium.
The most convenient storage method is hydrogen high-pressure (15-25 MPa) storage in steel gas-cylinders. There are many types of gas storage cylinders, which contain toxic and other hazardous gases or liquids [9-18]. These cylinders fill and empty quickly without complications. However, the important weakness of this method is the danger of explosively rapid release of gas. The second (related) weakness of steel gas-cylinders is their limited mass fraction storage capacity. They are made heavier than required for pressure retention to ensure safety against impact, puncture or crushing damage.
A primary object of the present invention is the creation of a new cellular storage system for compressed gas, which will combine safety with high capacity and yet be inexpensive and convenient, for use in aircraft and spacecraft. Such storage systems can be utilized also for ground vehicles as a hydrogen source for fuel cell electric generation.
In accordance with the present invention, by providing a storage system comprising a plurality of gas tight cells, preferably in modules, rather than a single gas cylinder of equivalent capacity, the danger of sudden total gas release will be reduced and the safety margin can therefore be reduced accordingly. The result is a much higher weight fraction of storage.
The idea of using a storage system with a plurality of cells formed of material having cellular structure as the basic gas storage block (cellular module) is the scientific and technical basis of a preferred aspect of this invention.
Multi cellular organisms demonstrate much more stability against environment negative impact than unicellular organisms. This principle underlies our invention. Therefore we have named our new device a Safe Cellular Storage (furtherxe2x80x94SCS).
The present invention is also embodied in the design of a system which incorporates means for automatically isolating destroyed gaseous storage cells from healthy cells, so that the SCS as a whole would remain efficient. This problem is solved by the system described and claimed below.